• Macro and Micro Structure of Wool Fiber

    The crimped configuration prevents wool fibers from aligning themselves too closely when being spun into yarn. As a result it is possible to have wool textile materials with air spaces. Occupying about two-third of the volume. The warmth of wool fabric is due more to the air spaces in the material then to fiber. more »
  • Relationship of Ortho-Cortex to the Crimp Wave in a Double-Crimped Wool

    The cortex of a crimped Merino wool fibre comprises two hemi-cylinders, which differ in both chemical and physical properties. The form of the crimp wave is related to alternations in the positions of the two cortical components within the fibre—the ortho- and the para-cortex1–4. The ortho-cortex tends to lie on the convex aspect of the crimp wave and the para-cortex on the concave aspect. more »
  • Intrinsic Curvature in Wool Fibres is Determined by the Relative Length of Orthocortical and Paracortical Cells

    Hair curvature underpins structural diversity and function in mammalian coats, but what causes curl in keratin hair fibres? To obtain structural datato determine one aspect of this question, we used confocal microscopy to provide in situ measurements of the two cell types that make up the cortex of merino wool fibres, which was chosen as a well-characterised model system representative of narrow diameter hairs, such as underhairs. We measured orthocortical and paracortical cross-sectional areas, and cortical cell lengths, within individual fibre snippets of defined uniplanar curvature. This allowed a direct test of two long-standing theories of the mechanism of curvature in hairs. We found evidence contradicting the theory that curvature results from there being more cells on the side of the fibre closest to the outside, or convex edge, of curvature. In all cases, the orthocortical cells close to the outside of curvature were longer than paracortical cells close to the inside of the curvature, which supports the theory that curvature is underpinned by differences in cell type length. However,the latter theory also implies that, for all fibres, curvature should correlate with the proportions of orthocortical and paracortical cells,and we found no evidence for this. In merino wool, it appears that the absolute length of cells of each type and proportion of cells varies from fibre to fibre, and only the difference between the length of the two cell types is important. Implications for curvature in higher diameter hairs,such as guard hairs and those on the human scalp, are discussed. more »
  • Protein Expression in Orthocortical and Paracortical Cells of Merino Wool Fibers

    Crimp and bulk, important wool fiber properties, are thought to be related to differences in the protein composition of the orthocortex and paracortex. Fiber morphological studies have demonstrated that the paracortex has a higher proportion of matrix and cysteine than the orthocortex. While there is some evidence for the differential expression of genes between these cell types in the follicle, this has not been demonstrated satisfactorily in the mature fiber. Using proteolytic digestion of wool fibers, followed by ultrasonic disruption to obtain relatively pure fractions of both cell types, the KAP3 high sulfur protein family was found to be present in higher concentrations in the paracortex. This significant finding provides an explanation for the higher cysteine content reported in the paracortex. This represents an advance in our understanding of protein expression variation in the orthocortex and paracortex, and how this relates to key physical and mechanical properties of wool fibers. more »
  • A Cure for the Dummy Cria Syndrome: The Squeeze Maneuver

    At the spring Calpaca (California affiliate of AOA), U.C. Davis Professor of Equine Medicine and Epidemiology Dr. John Madigan presented new research on the syndrome of dummy foals, and a methodology to reverse it. Equine neonatal maladjustment is more popularly referred to as dummy foal syndrome. Dr. Madigan's research findings have become known as the "squeeze method". Dr. Madigan is the principle researcher in the "Clinical Trial of the Madigan squeeze method for treatment of equine neonatal maladjustment syndrome." This groundbreaking research has clear application to the health and welfare of alpacas - read on to find out how. more »